Found this bumblebee sleeping in one of my sunflowers. If you're concerned about local pollinators then you can't go wrong planting sunflowers in your yard. I've counted at least eight different species of bees feeding from them.

As for flowers good for nectar feeders, i.e. insects to photograph, as well as feeding local populations, this season I have been impressed with Wild Carrot Daucus carota. This has other common names, such as Queen's Lace. It also looks very attractive in our garden.

Of course, the seed heads of your sunflowers will be very popular with birds.